Drag (or wind resistance) is proportional to velocity squared (as long as you aren't in a Stokesian environment ). Required power to overcome drag is proportional to velocity cubed.99trek5200 said:The hard part about that equation is that wind resistance is a function of the cube of the wind speed (to the power of 3) Thus, the resistance is less if you are riding at 10 mph into the wind compared to 20 mph into the wind. The resistance added by a gradient is constant regardless of how fast you are going.
That being said, I would throw out that a 20 mph wind at 15 mph riding speed is like a 5% grade. That is not based on anything scientific, just recollection of a few rides. (However, I am an estimator by trade and I did stay at a Holiday Inn Express last night)
Edit: Judging from the post that just beat me in, my estimate was about right. I was thinking 6% but knew that was too much.
if you are climbing out of the saddle. Which BTW is one of the things that makes hill climbing easier.....you can rest ione set of muscles (seated climbing) by using a different technique (standing climbing. Can't do that into a headwind. In addition, you get to rest downhill on a climbing course........with a headwind, no resst at all until you turn to come home.iliveonnitro said:Realize that different muscles are used during a climb than while on the flats. Also, you can always tuck to get more aerodynamic, but you can't ride through a hill
+1 Even though the effort feels about the same, there's a whole lot more satisfaction getting up a hill than there is pounding into the wind. And I'm tall, so headwinds make for extra suckage.walrus said:I'd rather climb a steep hill than ride into a strong wind anyday
At which point, the wind magically shifts direction, leaving you speechless in disbelieving frustration (except for the 4-letter words, of course).:mad2: :mad2:Len J said:...with a headwind, no resst at all until you turn to come home.
I am lousy. No Cat anything.serious said:acid_rider: I weigh ~150# and I was averaging ~23kmh into ~35kmh head wind for ~18km distance. Sounds like ~4% gradient?
Are you sure you can hold 23 km/hr into a 35 km/hr headwind for 45 minutes? As mentioned above, this means you can hold 330-340 watts over that time which is absolutley outstanding. As in Cat 1 outstanding!
The information provided you so far is factually correct, but everyone is missing a key point. The reported wind velocity that you hear is measured 30 feet (10 meters) or so above the ground, and far away from any buildings, trees, hills, or any other object that would affect the wind speed. The practical realities are that when riding a bike, even in very open country, the wind speed that the bike/rider experience is much less than the reported velocity. If there are any trees, houses, bushes, or even crops along the road, wind speeds are even lower. Plus, the wind speed at ground level is, by definition, zero, so we are always riding in a diminished wind space. IME, from knowing how huge an impact a headwind would have in a "wind tunnel" space, I would say that the actual winds we experience as riders are something like 1/4 to 1/3 of the reported wind velocity.acid_rider said:if I ride on a flat road into ~20 miles/per/hour headwind (~32kmh) how many degrees of gradient does it compare to, approximately? I am just looking for basic approximations, in absense of any hard data.